AI War: Alien Bundle | £3.00 | GamersGate | PC

AI War: Fleet Command is a space RTS with challenging adaptive AI and a huge selection of spaceships with which to do battle, bolstered by a wealth of DLC. The 2.5D graphics are extremely capable, though the experience is much more fun with other human space cadets to battle against (hint: the titular AI will smash your fleets into dust and laugh in your face).

Note that you can pick up the latest DLC pack, Ancient Shadows, for a discounted £1 - and save a little extra by plugging in voucher code "elder-geek.com" (without brackets).